http://bugzilla.kernel.org/faq.cgi says:

	"Q. What does a subsystem maintainer do?

	A. He or She will track new bugs and assign them to people or
	reject it for various reasons. They periodically check to make
	sure things are getting worked on and review fixes to make sure
	they are well written."

My impression is that almost none of the maintainers, especially the so-called
"subsystem maintainers in kernel tracker" (to be differentiated from people
listed in MAINTAINERS), has the power to assign bugs to people other than himself.